Chemical signaling is an important facet of vertebrate communication, and amphibians are no exception. However, very little is known about adult anuran (frog and toad) chemical communication, with the few studies that have investigated chemical sensing in adult anurans documenting species- and sex-biased behavioral responses to chemical cues. Varied life histories and reproductive pressures likely dictate these responses, but to better understand the prevalence and purpose of adult anuran olfaction across species, information on chemical sensing across a large number of species is needed. We investigated sex-biased adult Northern Leopard Frog (Lithobates pipiens) behavioral responses to familiar and unfamiliar conspecific chemical cues to determine the importance of olfaction in conspecific recognition. Our results indicate that adult females respond to conspecific cues, with females spending significantly more time investigating cue vs. control sides of the testing arena. Results for males were equivocal, with males responding much more variably. Comparisons of familiar vs. unfamiliar cues indicate that both sexes tend to spend more time near familiar cues, although this was not statistically significant. Females also responded to unfamiliar, opposite-sex conspecific cues, indicating chemical cues may be involved in mate identification for female Leopard Frogs. Unfamiliar, same-sex conspecific odors did not appear to influence behavior for either sex. Collectively, our results indicate that adult Northern Leopard Frogs utilize chemical sensing for conspecific recognition and further indicate a sex-bias in that sensing, with adult females exhibiting a stronger response than males. Future research should investigate aquatic vs. terrestrial cues and learned vs. innate odors of significance to Northern Leopard Frog adults.

The Neotropical lizard Tropidurus torquatus (Wied, 1820) is a generalist of habitats and habits, occurring both in preserved and in disturbed environments, including urban areas. In the present study, we analyzed the diet composition of populations of T. torquatus from two areas in the state of Rio de Janeiro in southeast Brazil: one with relatively little impact (Bravo 10, in Ilha da Marambaia) and one highly modified by anthropic influence (Rio de Janeiro Botanical Gardens). A total of 55 sexually mature lizards was collected (29 in the Botanical Gardens and 26 in Marambaia). We also sampled invertebrates on the ground and on vegetation to estimate the local potential availability of prey. Both populations presented relatively diverse diets, with ants and winged Hymenoptera (non-ant) being the predominant food items in the Botanical Gardens, whereas in Marambaia ants predominated, though termites were more representative in numerical terms (despite the low frequency of occurrence). In both areas, the proportion of plant material in the diet (10.6% of the total volume in the Botanical Gardens and 9.5% in Marambaia) was relatively low compared with other conspecific populations. Differences in diet between the two lizard populations were not significant, though the diets differed from the estimated local supply of prey in both areas. Our results suggest that the differences in the degree of anthropic disturbance between the two environments are not reflected in the diets of the lizards or in the availability of potential prey, with little variation between areas in both cases.

We present the conservation status and ecological characteristics (distribution, habitat preference, reproduction, population size, and structure) of an American Crocodile (Crocodylus acutus) population associated with the naval base “TN Tomas Vega” in Turiamo Bay, Aragua state, Venezuela. The sheltered coastal habitats, with freshwater or brackish water, as San Miguel River of Turiamo Bay, provide essential nursery habitats for hatchling American Crocodiles. During the breeding season, we looked for signs of nesting activity; however, because of continuous military exercises in the area, it is currently not known where nesting occurs. Based upon spotlight surveys of 6.7 km of survey routes, the resident American Crocodile population of Turiamo Bay was estimated at 38 American Crocodiles. Of this population, 6 sightings were classified as eyeshine only, 11 as class I, 14 as class II, 6 as class III, and 1 as class IV, exhibiting differential habitat association according to the size class. Encounter rates were highest in the brackish lagoon and low in the west coast and the San Miguel River, possibly because of the activities of the naval base causing evasive behavior by American Crocodiles. Our results indicate the C. acutus population in Turiamo Bay has been relatively stable in the past few years. However, it is important to accurately estimate the population size of C. acutus and protect the nesting and nursery habitats. Therefore, we recommend continuation of the population studies and involvement of environmental organizations to regulate anthropogenic activities in Turiamo Bay.

Loss of wetlands throughout the southeastern United States threatens the persistence of the region's highly diverse freshwater fauna. Losses are especially concerning for rare species that maintain small or fragmented ranges, zoogeographies that characterize many of the region's numerous freshwater endemics. We assayed nuclear and mitochondrial DNA sequence data from the Pine Barrens Treefrog (Hyla andersonii), a rare species distributed across the Atlantic and Gulf coastal plains. We hypothesized that the species' evolutionary history has been associated with changes in wetlands during Quaternary interglacials and that the contemporaneous extent of wetlands is positively correlated with population genetic diversity. Genetic variation was highest in North Carolina and South Carolina and lowest in New Jersey and Florida. Mean times to common ancestry ranged from 132,486 to 1,290,605 yr before present, and effective sizes ranged from 4,241 individuals in New Jersey to 403,718 individuals in North Carolina. Population migration rates were generally very low (<0.01), although higher rates were found between North Carolina and South Carolina. Total area of wetlands varied from 2,482 km² in South Carolina to 7,384 km² in North Carolina and has declined between 2001 and 2016. Genetic diversity was positively, although nonsignificantly, correlated to total amount of wetland habitat. Pine Barrens Treefrog is comprised of four relictual populations associated with ecological changes driven by climatic progressions of Quaternary interglacials, and collectively these populations conform to an abundant center model of evolution. All populations are conservatively designated management units, although evolutionarily significant unit status cannot be discounted.

Temperate snakes occupy overwintering sites for most of their annual life cycle. Microhabitat characteristics of the hibernaculum are largely undescribed, yet are paramount in ensuring snake overwintering survival. We hypothesized that snakes survive hibernation within a vertical subterranean space that we termed a “life zone” (LZ), that is aerobic and flood and frost free throughout winter. We studied an isolated, endangered population of Massasaugas (Sistrurus catenatus) inhabiting an anthropogenically altered peatland and monitored the subterranean habitat during a period of environmental stochasticity. Initial radio telemetry confirmed that snakes moved between altered and natural habitats during the active season and showed hibernation-site fidelity to either habitat. We used a grid of groundwater wells and frost tubes installed in each hibernation area to measure LZ characteristics over 11 consecutive winters. The LZ within the impacted area was periodically reduced to zero during a flood–freeze cycle, but the LZ in the natural area was maintained. Model selection analysis revealed that soil depth and flood status best predicted LZ size. Thermal buffering and groundwater dissolved oxygen increased with LZ size, and annual Massasauga encounters were significantly correlated with LZ size. This analysis suggests a population decline occurred when LZ size was reduced by flooding. Our data give support to the importance and maintenance of an LZ for successful snake hibernation. Our methods apply to subterranean hibernation habitats that are at risk of environmental stochasticity, causing flooding, freezing, or hypoxia.

The Peruvian endemic Lima Leaf-Toed Gecko (Phyllodactylus sentosus) is a critically endangered species with just a few known localities of occurrence, which are isolated from each other, within Lima City and in the Ica region. During 1 yr, we carried out monthly evaluations to determine the influence of the environmental factors on the size and population dynamics of this species in the Huaca Pucllana, as this area maintains one of the largest populations in Lima. We took body measurements and reproductive data and made a total of 1,924 captures and recaptures. The low catchability during the coldest months caused a population underestimation in which adults fluctuated between 69 and 313 and juveniles between 88 and 351 throughout the year for the study area of 6.07 ha. The catchability increased in the warmest months when the adult population peaked between December and January, whereas the population of juveniles peaked in December and April. We noted sexual dimorphism, the females being 8% longer than males. The reproductive cycle seems more similar to that of other species that inhabit the temperate zones, where females have oviductal eggs in spring and the appearance of young individuals occurs in mid- to late summer when food is abundant. We recommend carrying out one evaluation per year in Huaca Pucllana and in the other localities of occurrence of these geckos during summertime. We also recommend carrying out a management program including the translocation of individuals between Huaca Pucllana and the other four closest localities.

Long-term field studies of relatively long-lived lizards can reveal environmental influences and ontogenetic responses over the lifetime of an individual that would not be apparent in data from short-term field studies. Hence, we initiated a long-term (31-yr) study of a population of the Coachella Fringe-Toed Lizard, Uma inornata, to determine demographic (sex, size/age, population density) and environmental (rainfall) influences on HR size of individuals. Mark-and-recapture data and observations on marked individuals provided sufficient sightings to estimate HR size using minimum convex polygons for 45 males and 40 females varying from age 0 (birth year) to age 5. Home range size was positively correlated with age and body size and was nonlinearly correlated with individual growth. Males grew faster and attained larger body size than did females and had larger HRs than did females of similar age. However, the mean body size–adjusted HR size for adult U. inornata did not differ significantly by sex. Home range size was inversely related to density in males but showed no relationship to density in females. There was a significant inverse relationship between HR size and winter rainfall preceding a field season. Within individuals, HRs shifted geographically and increased in size over sequential years as individuals grew. The location of an HR's centroid shifted between 4 and 62 m between years (mean 28 m for males, 15 m for females). Hence, combining HR data from multiple years will overestimate the actual spatial usage of an individual during any single year.

Nile Monitors (Varanus niloticus) are large (up to 2.4 m in length), semiaquatic, carnivorous lizards native to Sub-Saharan Africa. Nile Monitors are reported from southeastern Florida near the Homestead Air Reserve Base in Miami-Dade County, around Southwest Ranches in Broward County, and from a reproducing population along the C-51 canal in Palm Beach County. This study characterizes the diet of Nile Monitors removed from Palm Beach and Broward counties. In 2012, Florida Fish and Wildlife Conservation Commission staff and University of Florida researchers began conducting monthly boat surveys along the C-51 canal and driving and walking surveys in Southwest Ranches. We used Nile Monitors removed with firearms or live traps from southeastern Florida from 2012 to 2016. We extracted gastrointestinal (GI) tracts and collected gut contents when present. We rinsed, sorted, dried, examined, and identified gut contents to the lowest taxonomic level possible. We examined 68 GI tracts (30 males, 37 females, 1 of undetermined sex) and identified 1,484 prey items from 65 individuals. We categorized prey items as gastropod, diplopod, malacostracan, arachnid, insect, fish, amphibian, reptile, reptile egg, bird, and mammal. Adult Nile Monitors exhibited the highest dietary diversity and evenness among size classes, and there was no observable difference in diet between males and females. Our observations confirm Nile Monitors are active foragers, and the combination of broad diet and active foraging makes it unlikely that food availability will limit distribution of these invasive lizards in Florida.

Trade-offs can cause conservation measures designed to improve habitat for one aspect of a species life history to inadvertently decrease its suitability in other ways. We explored the potential trade-off between thermal characteristics and risk of predation in important habitat for Timber Rattlesnakes (Crotalus horridus). Although typically a woodland species, pregnant C. horridus congregate in sunny, rocky clearings known as gestation sites that provide improved thermal habitat for embryonic development. Gestation sites can become overgrown with vegetation and, thus, sites may vary in canopy openness. We hypothesized that gestation sites with more canopy openness will be warmer but leave the snakes more exposed to predators. We used hemispherical photography to calculate canopy openness and operative temperature models to quantify thermal quality. Rattlesnake foam models and time-lapse cameras were deployed to quantify the relative predator richness and risk of predation. We found that more-open gestation sites were warmer than enclosed sites. We found that potential for predator encounters was similarly common regardless of gestation site canopy openness. However, we did find that predator species richness increased with canopy openness, with the most dangerous predators (raptors, mustelids, and felids) being only present at the most-open gestation sites. These results suggest that conservation actions for C. horridus that involve opening up the canopy at existing gestation sites may have unintended fitness consequences, as more dangerous predators appear to visit these more-open sites.

We modeled the ecological niche of the Yucatan Rattlesnake (Crotalus tzabcan) to map its environmental suitability, estimate its potential distribution, and identify the environmental factors that limit its geographic range within the Yucatan Peninsula (YP). Niche models were built to evaluate, separately and together, the ability of different sets of environmental predictors to explain the distribution of this species. The relative contribution percentage from each variable was calculated from the models with better predictive ability. Response curves were also constructed to observe the influence of predictors on the estimated environmental suitability for C. tzabcan. According to our niche models, even though the distribution of this species covers a large part of the YP, the northwest portion is likely the most environmentally suitable region. By contrast, populations from the north of Guatemala and Belize (south of the YP) are placed within the limits of the species' niche, and the environmental conditions toward the base of the peninsula are not suitable for this species. Precipitation was consistently the most important factor to explain the distribution of C. tzabcan. Although unlikely to directly affect the physiology of C. tzabcan, precipitation affects other factors (e.g., predator, prey, and competitor densities; undergrowth coverage; and relative humidity) that influence survival. Our study contributes new and detailed knowledge of the distribution ecology of a species that was once the most culturally valued in the YP.

Parasitic helminths are an almost universal feature of vertebrate animals, but reptiles are among the hosts with the most depauperate parasite communities. Biological traits of reptiles are considered to be among the key reasons that explain low helminth diversity; therefore, insights from a wide range of reptile hosts are helpful to understanding the ecology of parasitic helminths. We analyzed helminth fauna in two lacertids, Psammodromus algirus and Psammodromus edwarsianus (Squamata: Lacertidae), and one skink, Chalcides bedriagai (Squamata: Scincidae), three common species of Mediterranean woodlands that differ in their ecological conditions and in lifestyles that are linked to habitat use. We examined a total of 102 P. algirus, 27 P. edwarsianus, and 23 C. bedriagai from mountain landscapes in eastern Iberia. We found three helminth species, the nematodes Parapharyngodon echinatus and Spauligodon sp., and the cestode Mesocestoides sp. We report new reptile hosts for two helminth species: the skink C. bedriagai for the nematode P. echinatus and the lizard Psammodromus algirus for the nematode Spauligodon sp. We also provide the second record of the larval forms of the cestode Mesocestoides sp. in the lizard P. edwarsianus from the Iberian Peninsula. Interestingly, prevalence of infection was much higher in the skink than it was in the two lacertid lizards. Therefore, a subterranean skink lifestyle may determine the incidence of helminth parasites when compared to the ground-dwelling lizard species. Similar to other reptile hosts, the helminth fauna of our focal lizard species was poor and mainly composed by Pharyngodonidae nematodes that are often detected in insectivorous reptiles.

Natural history collections are important data repositories, but different chemical treatments of specimens can influence morphological measurements and DNA extraction, complicating taxonomic and conservation decisions dependent upon these data. One such example is the Bay Springs Salamander (Plethodon ainsworthi), the only United States amphibian categorized as Extinct by the International Union for Conservation of Nature (IUCN). Recent research has proposed that P. ainsworthi is an invalid taxon, arguing that the 55-yr-old type specimens' morphological distinctiveness from syntopic Plethodon mississippi is a preservation artifact. To address this controversy, we tested for morphological changes across five experimental treatments in proxy Plethodon shermani specimens and we reexamined the datasets used to support the invalidity of P. ainsworthi. We also tested recently developed DNA extraction techniques on the putatively formalin-fixed P. ainsworthi holotype. We used Bayesian models to demonstrate that preservation method can differentially bias morphological measurements, with most methods causing lower estimates of mass and modestly higher estimates of snout–vent length: head width ratio. These results are broadly consistent with previous studies of other vertebrates, but inconsistent with the hypothesis that P. ainsworthi type specimens are actually poorly preserved P. mississippi. Attempts to extract DNA from the P. ainsworthi holotype unfortunately proved unsuccessful, preventing conclusive resolution of its status and emphasizing the limitations of promising new methods. Nonetheless, we tentatively recommend continued recognition of P. ainsworthi as a valid but possibly extinct taxon. More generally, we invite all authors who study preserved specimens to recognize and report how certain chemical treatments might impact their results.

American Alligators (Alligator mississippiensis) are known to consume venomous Pit Viper snakes, apparently with no ill effects. Alligators handle venomous and nonvenomous snakes similarly during consumption, indicating that alligators may possess a physiological resistance to venom. In our study, we tested the ability of alligator blood sera to inhibit the activity of two of the primary toxins in Eastern Copperhead (Agkistrodon contortrix) venom, hemolytic toxins and snake venom metalloproteinases (SVMP). Specifically, we compared relative venom activity following incubation with alligator sera to a venom-only control as well as venom incubated with serum from a species lacking venom resistance (House Mouse; Mus musculus). In comparison to controls, alligator sera significantly reduced SVMP activity, although we observed no effect of alligator sera on hemolytic activity. Interestingly, we detected individual variation with respect to hemolytic activity such that inhibition was positively related with both alligator length and body condition. Our results provide evidence that alligator serum is capable of inhibiting at least one of the primary toxins present in pit viper venom.

Ecosystem disturbance through urbanization and agriculture, coupled with anthropogenic climate change, poses a pervasive threat to ecosystem health. Such landscape disturbance can manifest as salinization, particularly in Australia. Increasing salinization of both soils and waterways has the potential to render habitats unsuitable for amphibians. However, some species exist naturally in brackish and saline habitats, which suggests the capacity to adapt to salinization. To assess this adaptability in amphibians, we examined current brackish habitat utilization by a common Australian Froglet, Crinia signifera, and determined the tolerance of eggs and tadpoles of this species to acute and chronic exposure to brackish water. Crinia signifera lay eggs in brackish water and, through laboratory experiments, we determined that short-term survival in water up to 7.5 parts per thousand (ppt) salinity is possible but may vary among populations. Chronic exposure experiments demonstrated that C. signifera can successfully complete larval development to metamorphosis in brackish water (up to 5.0 ppt). Data presented here, together with previously published reports of salinity tolerance in other Australian frog species, collectively demonstrate a capacity for adaptation to landscape salinization. This has probably been mediated by an evolutionary history in the saline landscapes so common in Australia.

We describe a new frog species of the megadiverse genus Pristimantis from the Chapada Diamantina, a regional designation of the Espinhaço mountain range in the state of Bahia, northeastern Brazil. We assign the new species to the genus Pristimantis, P. conspicillatus group, based on its phylogenetic position. This is the second rupicolous species of Pristimantis and the fourth species inhabiting northeastern Brazil. The new species is characterized by the following combination of characters: 1) dorsum background color light brown to yellowish-brown, maculated with blackish-brown marks, resembling a granite rock surface; 2) dorsum granular; 3) venter areolate; 4) dentigerous process of the vomer ovoid; 5) snout rounded or truncate in dorsal view; 6) snout rounded in profile; 7) dorsolateral folds absent; 8) finger fringes absent; 9) toe fringes weakly developed; 10) double, poorly developed nuptial pads; 11) vocal slits present in the male; 12) advertisement call composed of one note; 13) call duration 0.011–0.086 s; 14) dominant frequency varying from 2.41 to 3.49 kHz; and 15) decreasing amplitude modulation from the beginning to the end of call. We recovered the new species outside the clade containing the other three nominal species of Pristimantis from northeastern Brazil, as the sister species of P. gaigei, a species from Costa Rica, Panama, and Colombia. The new species seems to be restricted to the high-elevation areas (870–1,800 m a.s.l.) of the Chapada Diamantina, Central Bahia, Brazil. Both the genus Pristimantis and the P. conspicillatus group still lack morphological synapomorphies, and a thorough systematic review based on a stringent phylogenetic hypothesis is necessary for a better understanding of the evolution of these important lineages of Neotropical frogs.

Apostolepis mariae and Apostolepis thalesdelemai are two simultaneously described Elapomorphini snake species for two mountain ranges of Caatinga Enclaves moist forests in the state of Ceará, northeastern Brazil. Both species were differentiated from congeners and from one another based exclusively on external morphology. We examined the type specimens as well as a comprehensive series of specimens for both species and provide evidence for the recognition of both taxa as conspecific. We apply Article 24.2.1 of the International Code of Zoological Nomenclature (ICZN) that provides guidelines for taxonomic status precedence for both species based on the principle of the first reviser decision. Based on the ICZN code, we gave precedence for A. thalesdelemai over A. mariae. Finally, we provide a complementary diagnosis for A. thalesdelemai along with comments on its geographic distribution, natural history, and conservation.

We describe a new species of plethodontid salamander of the genus Pseudoeurycea from the mountains of central Veracruz, Mexico. This species can be distinguished from its congeners by color pattern and morphological characters. The molecular phylogenetic analysis indicates that Pseudoeurycea granitum sp. nov. is part of the Pseudoeurycea leprosa subclade and is closely related to Pseudoeurycea nigromaculata, Pseudoeurycea firscheini, and Pseudoeurycea lynchi. Known localities for P. granitum sp. nov. are mostly located in cloud forest fragments, with one from a shaded coffee plantation and one from an ecotone between cloud forest and pine–oak forest, all immersed in highly modified landscapes. This suggests the need to implement a conservation strategy in order to preserve the limited remaining habitat for this species.